Lexmark C 746 Service Manual

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Printhead removal, installation, and adjustment
See “Printhead assembly” on page 7-11 for the part number.
Service tip—Testing the new printhead
See “Printhead verification” on page 3-39 for quick way to verify that the existing printhead is failing 
before installing the new printhead. If the new printhead also fails, the existing printhead is probably 
working properly, so the system board is probably the failing component.
Printhead removal
1.
Turn...

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Warning:  To avoid damaging the photoconductor drum, place the transfer module with the 
photoconductor units on a clean surface. Never expose the photoconductor units to light for a prolonged 
period of time. Place a clean, dry cloth over the transfer module and photoconductor units until they are 
required.
8.Remove all of the toner cartridges.
9.Remove the right cover and the right side cover (attached). See “Right cover removal” on page 4-51. 
10.Remove...

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13.Remove the three printhead mounting screws (D). 

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14.Remove the printhead alignment screw cover (E).
15.While still holding the printhead in place, loosen the printhead alignment screw (F) until the printhead 
comes out.
Warning:  Secure the printhead when loosening the printhead alignment screw. Failure to do this allows 
the printhead to fall out of the printer, potentially damaging the printhead. 
Install the printhead and replace parts
Warning:  
•When reinstalling the printhead, it is important to...

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2.Loosely attach the three printhead mounting screws (B).
Warning:  Do not fully tighten the printhead mounting screws until skew has been adjusted. 
3.Lightly tighten the alignment screw (C). 
4.Feed the ground cable through the hole in bottom leftside frame. 

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5.Replace the system board support shield screws (E): 
a.Loosely attach the two mounting screws (E2)
b.Set the system board support shield in place.
Check that the ribbon mirror motor cable (white) and the printhead cable (bottom) do not rub against 
the edges of the frame.
c.Replace the remaining system board support shield screws in the following order:
•Replace the four screws (E1) from the inner right side of the support shield.
•Tighten the two...

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6.Replace the system board. 
a.Place the system board in position.
Check that the mirror motor cable and the printhead cable do not rub against the edges of the frame.
b.Replace the nine screws (F) in the system board in the following order:
•Loosely attach the four corners (F1) in a clockwise order, beginning with the left top corner.
•Replace the USB connector screw (F2).
•Loosely attach the left center side, top center, and right center side (F3)....

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d.Replace all the screws (G) from the left side of the printer, including:
•Ethernet port connector (1 screws)
•Modem shield (1 screws)
•Hard disk shield (2 screws)
•Ground screw (1 screw)
Note:  Be sure to attach the ground wire (H) to the ground screw.
e.Reconnect all the cables to the system board. Use the diagram below as a guideline.
Warning:  Be careful in reconnecting the printhead ribbon cable (J). It can be damaged and should be 
handled carefully....

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d.Reconnect the cable in connector JLVPS1 on the system board.
8.Replace the right cover.
a.Slide the right cover up until it locks into position.
Be sure the tab in the top access cover engages the slot in the right cover. 
b.Replace the screw at the bottom of the rear frame cover.
c.Replace the two screws securing the right cover at the bottom.
d.Replace the metal screw at the bottom on the inside front cover
e.Replace the plastic screw at the top on...

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Right bell crank assembly removal
See “Right bellcrank assembly, with spring” on page 7-7 for the part number.
1.Remove the right cover. See “Right cover removal” on page 4-51.
2.Remove the C-clip (A).
3.Remove the right bell crank assembly.
A